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Technical content
Features
700mA Output Current Internal 0.7 Ω 26V Power MOSFET Switch Wide 7 to 26V Operating Input Range 20 μA Shutdown Mode Current Typical 4% Output Current Accuracy Signal pin ON / OFF and Brightness Control Adjustable Soft-Start Up to 95% Efficiency Up to 1MHz Switching Frequency Internal Dimming Filter Package: SOT23-5L
Applications
Low Voltage Halogen replacement LEDs LED back-up lighting Typical Application Circuit
This datasheet contains new product informat ion. Feeling Technology reserves the right s to modify the product specification wi thout notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Function Block Diagram Pin Descriptions SOT23-5L Name No. I / O Description LX 1 O Power Switch Output GND 2 P IC Ground ADJ 3 I Multi Function ON / OFF& Brightness Control ISENSE 4 I Current Sense Resistor Connected VIN 5 P IC Power Supply
This datasheet contains new product informat ion. Feeling Technology reserves the right s to modify the product specification wi thout notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Marking Information SOT23-5L Lot Number: Wafer lot number’s last two digits For Example: 132362TB 62 Year: Production year’s last digit Part Number Code: Part number identification code for this product. It should be always “AQ”.
This datasheet contains new product informat ion. Feeling Technology reserves the right s to modify the product specification wi thout notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product.
Ordering Information
Part Number Code Operating Temperature Package MOQ Description FP7151KR-G1 AQ -40℃ ~ 85 ℃ SOT23-5L 3000EA Tape & Reel Absolute Maximum Ratings Parameter Symbol Conditions Min. Typ. Max. Unit Supply Voltage V IN -0.3 26 V ISENSE Voltage V SENSE Measured with Respect to V IN +0.3 -5 V LX Input Voltage V LX -0.3 26 V Adjust Pin Input Voltage V ADJ -0.3 6 V Power Dissipation P D SOT23-5L @TA=25℃ 570 mW Thermal Resistance (Note1) θJA SOT23-5L +220 ℃ / W Junction Temperature T J +150 ℃ Operating Temperature T OP -40 +85 ℃ Storage Temperature T ST -65 +150 ℃ Lead Temperature (soldering, 10 sec) +260 ℃ Note1: θJA is measured in the natural convection at T A=25°C on a low effective thermal conductivity test board of JEDEC 51-3 thermal measurement standard. IR Re-flow Soldering Curve
This datasheet contains new product informat ion. Feeling Technology reserves the right s to modify the product specification wi thout notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Parameter Symbol Conditions Min. Typ. Max. Unit Input voltage V IN 7 26 V Internal Regulator Start-up Threshold VSU V IN Rising 4.8 V Quiescent Supply Current with Output off IINQoff ADJ pin Grounded 15 20 µA Quiescent Supply Current with Output Switching IINQon ADJ pin Floating f=250kHz 400 800 µA Mean Current Sense Threshold Voltage (Defines LED Current Setting Accuracy) VSENSE Measured on ISENSE pin with Respect to VIN VADJ =1.25V 95 100 105 mV Sense Threshold Hysteresis V SENSEHYS ±15 % ISENSE pin Input Current I SENSE V SENSE =VIN -0.1 3 10 µA Internal Reference Voltage V REF Measured on ADJ pin with pin Floating 1.21 1.25 1.29 V Temperature Coefficient of VREF △VREF / △T 50 ppm/℃ External Control Voltage Range on ADJ pin for Dc Brightness Control (1) VADJ 0.3 2.5 V DC Voltage on ADJ pin to Switch Device from Active (on) State to Quiescent (off) State VADJoff V ADJ Falling 0.15 0.2 0.25 V DC Voltage on ADJ pin to Switch Device from Quiescent (off) state to Active (on) State VADJon V ADJ Rising 0.2 0.25 0.3 V Resistance Between ADJ pin and VREF RADJ 135 250 kΩ Continuous LX Switch Current I LXmean 0.7 A LX Switch ‘On’ Resistance R LX 0.7 0.9 Ω LX Switch Leakage Current I LX (leak) 1 µA
This datasheet contains new product informat ion. Feeling Technology reserves the right s to modify the product specification wi thout notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Parameter Symbol Conditions Min. Typ. Max. Unit Duty cycle range of PWM signal applied to ADJ pin during low frequency PWM dimming mode DPWM (LF) PWM frequency <500Hz PWM amplitude= VREF Measured on ADJ pin 0.01 1 Brightness Control Range 100:1 Duty cycle range of PWM signal applied to ADJ pin during high frequency PWM dimming mode DPWM (HF) PWM frequency >10kHz PWM amplitude= VREF Measured on ADJ pin 0.16 1 Brightness Control Range 5 :1 Soft Start Time T SS Time taken for output current to reach 90% of final Value after voltage on ADJ pin has risen above 0.3V 500 µs Operating Frequency (See Graphs for more Detail) fLX ADJ pin floating L=100μH (0.82Ω) IOUT=700mA @ VLED=3.4V Driving 1 LED
250 KHz
Minimum Switch ‘ON’ Time T ONmin LX switch ‘ON’ 200 ns Minimum Switch ‘OFF’ Time T OFFmin LX switch ‘OFF’ 200 ns Recommended Maximum Operating Frequency fLXmax 1 MHz Recommended Duty Cycle Range of Output Switch at fLXmax DLX 0.3 0.7 Internal Comparator Propagation Delay TPD 50 ns Notes： 1. 100% brightness corresponds to VADJ = VADJ (nom) = VREF. Driving the ADJ pin above VREF will increase the VSENSE threshold and output current proportionally.
This datasheet contains new product informat ion. Feeling Technology reserves the right s to modify the product specification wi thout notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Typical Operating Characteristics (VCC=12V, Single LED,TA= 25°C,L=100uH, unless otherwise noted) Input Voltage vs. Vsense Voltage 100 102 5 1 01 52 02 53 0 Input Voltage(V) Vsense(mV) Input Voltage vs. Vsense Voltage 5 1 01 52 02 53 0 Input Voltage(V) Vsense(%) Input Voltage vs. ILED 0.55 0.56 0.57 0.58 0.59 0.6 0.61 0.62 0.63 5 1 01 52 02 53 0 Input Voltage(V) ILED(A) Temperature vs. ILED 0.5 0.54 0.58 0.62 0.66 0.7 - 4 0 - 2 00 2 04 06 08 0 Temperature(℃) ILED(A) Vadj vs. ILED L=47uH , Rs=0.31ohm 100 200 300 400 500 600 700 00 . 511 . 522 . 53 Vadj(V) ILED(mA) Set Curremt Actual Current Vadj vs. ILED L=100uH , Rs=0.31ohm 100 200 300 400 500 600 700 00 . 511 . 522 . 53 Vadj(V) ILED(mA) Set Current Actual Current Vadj vs. Vsense ERR -20 -15 -10 Vadj(V) Vsense ERR(%) Rs vs. ILED 0.2 0.4 0.6 0.8 RS(Ω) ILED(A) ILED=0.6A Suggestion: 0.3V≤Vadj≤2.5V L=47uH
This datasheet contains new product informat ion. Feeling Technology reserves the right s to modify the product specification wi thout notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Function Description Operation The FP7151 is a continuous mode inductive step-down converter that is easily to be configured in varies applications ranging from 7V~26V input. The converter employs a high side current sensing resistor RS to detect and regulate the LED current. The voltage across the current sensing resistor is kept measured and regulated in 100mV±15mV range. The internal 1.25V reference voltage is utilized to provide a 0.25V reference for enabling the part and a 1.25V pulling-up voltage as current reference voltage. When V ADJ>0.25V the output of the comparator becomes high and the other blocks are enabled. When input voltage VIN is first applied, the initial current in L1 and RS is zero and there is no output from the current sense circuit. Under this condition, the output of comparator is high. This turns on an internal switch and switches the SW pin low, causing current to flow from VIN to ground, via RS, L1 and the LED(s). The current rises at a rate det ermined by VIN and L1 to produce a voltage ramp across RS. When (V IN - VSENSE) > 115mV, the output of Comparator switches low and the switch turns off. The current flowing on the RS decreases at another rate. When (V IN- VSENSE) < 85mV, the switch turns on again and the mean current on the LED is 100mV/RS. Adjusting output current The device contains a low pass filter between t he ADJ pin and the threshold comparator and an internal current limiting resistor (250k nom) between ADJ and the internal reference voltage. This allows the ADJ pin to be overdriven with either DC or pulse signals to change the V SENSE switching threshold and adjust the output current. Output Shutdown The output of the low pass filter dr ives the shutdown circuit. When the input voltage to this circuit falls below the threshold (0.2V nom), the internal re gulator and the output switch are turned off. The voltage reference remains powered during shutdown to provide the bias current for the shutdown circuit. Quiescent supply current during shutdown is nominally 15uA and switch leakage is below 1uA. Dimming Control The FP7151 provides two dimming methods: PWM dimming and DC analog dimming. To use PWM dimming, apply a square wave to the EN/DIM pin. To used analog dimming, apply a 0.3V~2.5V DC voltage to this pin.
This datasheet contains new product informat ion. Feeling Technology reserves the right s to modify the product specification wi thout notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product.
Application Information
The LED current is identical and set by the current setting resistor between the VIN pin and ISENSE pin. To set the LED current according to the following equation: RS 0.1=ILED For RS=0.33Ω, the LED current is set to 300mA Shutdown Mode Taking the ADJ pin to a voltage below 0.2V will turn off the output and the supply current will fall to a low standby level of 15μA nominal. Soft Start The voltage on the ADJ pin is the inductor current reference. An external capacitor from the ADJ pin to ground provides a soft-start delay. When V IN starts, internal voltage source charges the capacitor from 0V to 1.25V to fulfill soft-start function. Capacitor selection A low ESR capacitor should be used for input decoupling, as the ESR of this capacitor appears in series with the supply source impedance and lowers overall efficiency. This capacitor has to supply the relatively high peak current to the coil and smooth the current ripple on the input supply. A minimum value of 4.7uF is acceptable if the input source is close to the device, but higher values will improve performance at lower input voltages, especially when the source impedance is high. The input capacitor should be placed as close as possible to the IC. For maximum stability over temperature and voltage, capacitors with X7R, X5R, or better dielectric are recommended. Capacitors with Y5V dielectric are not suitable for decoupling in this application and should not be used. Reducing output ripple Peak to peak ripple current in the LED(s) can be reduced, if required, by shunting a capacitor CLED across the LED(s)
This datasheet contains new product informat ion. Feeling Technology reserves the right s to modify the product specification wi thout notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Inductor selection Recommended inductor values for the FP7151 are in the range 47uH to 100uH. Higher values of inductance are recommended at higher supply voltages in order to minimize errors due to switching delays, which result in increased ripple and lower efficiency. Higher values of inductance also result in a smaller change in output current over the supply voltage range. The inductor should be mounted as close to the device as possible with low resistance connections to the LX and VIN pins. The chosen coil should have a saturation current higher than the peak output current and a co ntinuous current rating above the required mean output current. DC Dimming I OUTDC= 0.08*VADJ/RS [for 0.3< VADJ <2.5V]. The ADJ pin can be driven by an external DC voltage (VADJ), to adjust the output current to a value bel ow the nominal average value defined by RS. The LED current decreases linearly with the V ADJ when 0.3V ≤ VADJ ≤ 2.5V, R S must be increased in proportion to prevent IOUTDC exceeding 700mA maximum. When the VADJ falls below the threshold, 0.2V, the output switch is turned off which allows PWM dimming. PWM Dimming A Pulse Width Modulated (PWM) signal with duty cycle D PWM can be applied to the ADJ pin, The PWM signal is recommended above 50kHz.As shown below, to adjust the output current to a value above or below the nominal average value set by resistor RS:
This datasheet contains new product informat ion. Feeling Technology reserves the right s to modify the product specification wi thout notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. PC Board Layout Checklist 1. the capacitor C1 has to be placed as close as possible to V IN 2. The sense resistor RS has to be placed as close as possible to V IN and ISENSE 3. The D1 anode, the SW pin and the inductor L1 have to be placed as close as possible to avoid ringing Suggested Layout
This datasheet contains new product informat ion. Feeling Technology reserves the right s to modify the product specification wi thout notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Typical Application
This datasheet contains new product informat ion. Feeling Technology reserves the right s to modify the product specification wi thout notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product. Package Outline SOT23-5L UNIT: mm Note: 1. Package dimensions are in compliance with JEDEC outline: MO-178 AA. 2. Dimension “D” does not include moldi ng flash, protrusions or gate burrs. 3. Dimension “E1” does not include inter-lead flash or protrusions. Symbols Min. (mm) Max.(mm) A 1.050 1.350 A1 0.050 0.150 A2 1.000 1.200 b 0.250 0.500 c 0.080 0.200 D 2.700 3.000 E 2.600 3.000 E1 1.500 1.700 e 0.950 BSC e1 1.900 BSC L 0.300 0.550 L1 0.600 REF L2 0.250 BSC θ° 0 ° 10 ° θ1° 3° 7° θ2° 6° 10 °